Our team has been seeing this since we migrated to VS2015. When working with a solution in our depot, we get many complaints in the output window along the lines of
"->fstat -Ol I:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits
[E_ERROR] Path 'I:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\type_traits' is not under client's root 'I:\Workspace'."
"->fstat -Olhp c:\Users\jhenderson.EU\AppData\Roaming\Microsoft\VisualStudio\14.0\SingleFileISense\_sfi_527a4aa7-10d8-4e02-ba52-fb44e1bb1138_.vcxproj.filters
[E_ERROR] Path 'c:\Users\jhenderson.EU\AppData\Roaming\Microsoft\VisualStudio\14.0\SingleFileISense\_sfi_527a4aa7-10d8-4e02-ba52-fb44e1bb1138_.vcxproj.filters' is not under client's root 'I:\Workspace'."
Also, it tries to do operations on system files when an assert fires) n the middle of debugging sessions, and pops up an annoying dialog box:
"add -f c:\Program Files (x86)\Windows Kits\10\Source\10.0.10150.0\ucrt\internal\report_runtime_error.cpp
Path 'c:\Program Files (x86)\Windows Kits\10\Source\10.0.10150.0\ucrt\internal\report_runtime_error.cpp' is not under client's root 'I:\Workspace'."
These files aren't something we should be checking in, and I wouldn't expect Perforce to try to do anything to them. They're not part of our solution, but may sometimes be listed in the "External Dependencies".
I was able to create a simple project that exhibits this behaviour. It needs to use "Multi-Threaded Debug" Code Generation settings (/MTd) - the DLL version does not exhibit the same issue. I've attached it to this page.
Could you let me know what, if anything, I can do to resolve this, as it is very annoying!